1. Field of the Invention
The invention is a process for producing patterned chromate film on metal substrates.
2. Description of the Prior Art
Chromate films are extensively used in commerce as protection against corrosion and as an antistaining film. A large variety of chromating procedures have been developed to produce chromate films on various metal surfaces. However, there has been little or no need for chromate patterned surfaces with high dimensional tolerances. For this reason procedures for producing accurately patterned chromate films are not well known. Recently the need for such films has become apparent due to the possibility that chromate films may be useful in the fabrication of various devices including electronic circuits. Although various masking procedures may be used to produce patterned chromate films, it is highly desirable to have a more direct procedure requiring fewer steps and possibly less time so as to increase fabrication efficiency and economy. Also, higher dimensional tolerance is desirable particularly in electronic device fabrication so as to obtain smaller devices and greater packing density as well as greater reliability.